{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{4}{c}}
\hline\hline
                    &\multicolumn{1}{c}{\specialcell{\;\;\;\; Arsenic \\ contamination \\ \;\;\;\; (WHO \\ \;\; threshold)}}&\multicolumn{1}{c}{\specialcell{\;\;\;\;\;Arsenic \\ contamination \\ (Bangladeshi \\ \;\; threshold)}}&\multicolumn{1}{c}{\specialcell{\;\;\;\; Arsenic \\ contamination \\ \;\;\;\;\; level}}&\multicolumn{1}{c}{\specialcell{\;\;\;\;\;\; Fecal \\ contamination}}\\\cmidrule(lr){2-2}\cmidrule(lr){3-3}\cmidrule(lr){4-4}\cmidrule(lr){5-5}
                    &\multicolumn{1}{c}{(1)}   &\multicolumn{1}{c}{(2)}   &\multicolumn{1}{c}{(3)}   &\multicolumn{1}{c}{(4)}   \\
\hline
Treated             &      -0.056** &      -0.027   &      -0.155   &      -0.021   \\
                    &     (0.023)   &     (0.019)   &     (3.648)   &     (0.019)   \\
Constant            &      -0.068***&      -0.008   &       7.642** &      -0.035** \\
                    &     (0.018)   &     (0.015)   &     (3.167)   &     (0.015)   \\
\hline
p-value (analytical)&        0.02   &        0.15   &        0.97   &        0.28   \\
p-value (RBI)       &        0.04   &        0.23   &        0.95   &        0.38   \\
Mean at baseline    &        0.69   &        0.30   &       37.27   &        0.55   \\
R$^2$               &        0.03   &        0.02   &        0.07   &        0.04   \\
N                   &        6051   &        6051   &        6051   &        6051   \\
\hline\hline
\end{tabular}
}
